1. Field of the Invention
This patent relates to packaging for large appliances such as washers, dryers and refrigerators. More particularly, this patent relates to an improved tubular-type corner post that flexes when wrapped tightly with plastic film but is "spring loaded" in the sense that, when fully compressed, it imparts an outward force on the plastic film to keep the plastic film tight.
2. Description of the Related Art
Corner posts are used to cushion the corners of large, heavy appliances (such as washers, dryers, refrigerators, dishwashers and stoves) during storage and transport and to provide resistance against axially directed compressive loads. Typically, the appliance is placed on and fastened to a base pad having dimensions greater than the width and length (depth) of the appliance to accommodate the corner posts. A protective corrugated sleeve is placed over the appliance and inside the perimeter of the base to form four container sidewalls. The corner posts are then inserted around the corners of the appliance to protect the product from scratching and denting during shipping and handling. A corrugated top serves as the container lid. Metal or plastic straps may be wrapped around the container to better secure the corner posts between the appliance corners and the corrugated container walls.
One typical type of corner post is that made of multiple layers of paper wound into a convolute (coiled) tube. Adhesive is used to bond the paper layers. Before the adhesive dries, the tube is formed into the desired shape, typically one with a modified "L" shaped cross section to fit snugly between the corner of an appliance and the inner corner of the appliance container.
Numerous patents disclose corner posts made from convolutely wound paper. For example, Gardner U.S. Pat. No. 4,482,054, issued Dec. 7, 1993, discloses a corner post made of a single piece of convolutely wound paper having fibers disposed longitudinally. Numerous beaded configurations are disclosed.
Ortlieb U.S. Pat. No. 5,593,039 discloses a corner post made from convolutely wound paper and including a shoulder defined by a laterally turned portion of an inner wall. The corner post is designed to be used with appliances having projecting handles and the like.
Hughes U.S. Pat. No. 5,267,651, issued Dec. 7, 1993, discloses yet another corner post made from convolutely wound paper. Stiffening beads in each leg and integrally formed in the outside wall extend into free engagement with the inner wall. When a transverse force is applied to one leg of the post, the stiffening bead in that leg partially collapses on itself and slides along the inner wall.
While these and other corner posts are most often used to cushion and protect appliances packaged in cartons having vertical walls made of corrugated cardboard, they can also be used with packages employing heavy duty clear plastic film. The plastic film then serves as the sides of the package. The resulting package allows a substantially full view of the appliance.
However, one disadvantage of using conventional corner posts with plastic film packages is that, when the corner posts are placed around the corners of a product and the entire assembly is wrapped tightly in clear plastic film, the film tends to become loose over time. A second disadvantage of conventional tubular type corner posts is that they can collapse when subjected to very strong compressive forces, such as that which is applied when an appliance package is wrapped very tightly in plastic film.
Thus it is an object of the present invention to provide a corner post that can be used to protect products wrapped tightly in plastic film.
Another object of the present invention is to provide a spring loaded corner post that exerts an outward force on the plastic film when in a compressed state so that the plastic wrap stays tight during shipping and storage.
Yet another object of the present invention is to provide a corner post that does not collapse or lose its protective ability when subjected to compressive forces from tightly wrapped plastic film.
Still another object of the present invention is to provide a corner post whose strength is enhanced when it is wrapped tightly with plastic film.
Further and additional objects will appear from the description, accompanying drawings, and appended claims.